Tolerance display system

ABSTRACT

The tolerance display system that allows workers to easily obtain accurate size information in actual worksites is provided. The tolerance display system includes a tolerance display device ( 10 ). The tolerance display device ( 10 ) includes storage means storing standards data/files related to general tolerance, information input means ( 12  to  22, 26, 28,  etc.) for inputting prescribed information, operation means for reading out standards data related to a general tolerance from storage means based on data input by the information input means and calculating limits of size, and output means ( 24 ) for displaying the standards data, the limits of size and the like. The information input means includes an industry kind menu input portion ( 12 ) for selecting and inputting a product name of a desired industry kind, a specified condition input portion ( 16, 18, 20 ) for inputting specified conditions such as a special item, a tolerance class, a basic dimension, and a numerical value/arithmetic operator input portion ( 22 ) for inputting a numerical value/an arithmetic operator.

TECHNICAL FIELD

[0001] The present invention relates to a tolerance display system, and more particularly, to a tolerance display system used by workers engaged in working of various products such as iron castings, open die forgings, aluminum alloy castings, steel castings, metallic sintered products, die castings, parts formed by shear working from sheet metal, and parts formed by press working from sheet metal. The display system displays general tolerance without direct individual tolerance indication in working drawings, and limits of size calculated based on them.

BACKGROUND ART

[0002] In manufacture drawings used in worksites in various manufacturing and machining industries, dimensional tolerance for example based on national standards are inserted/indicated. The general dimensional tolerance (permissible deviation in dimension without tolerance indication) meant for simplifying indications in drawings have no individual tolerance indication and no tolerance indication for individual sizes on drawings, but are given collectively in the form of a list of standards. The general tolerance is mainly applied to the dimensions of parts that do not require particularly high precision in view of their functions.

[0003] In working in actual worksites, the general tolerance is still very important and indispensable information in manufacturing high quality products, but they are not included in the dimensions given in drawings.

[0004] Meanwhile, conventionally, in worksites in various manufacturing and machining industries, general tolerance is known to workers only based on their sense and experience of many years or through a list of standards. In some cases, general tolerance values available from the standards list are used to calculate limits of size on paper or using a desktop calculator (hereinafter simply as “calculator”), and the results are added or used for correction to the sizes given on the manufacture drawings.

[0005] According to the conventional method, however, the operation heavily depends on the experience and sense of workers in other words on their memory, accurate limits of size are sometimes not available when the workers are in error. It involves a labor in itself to go through the standards list, carry out calculation on paper or using a calculator based on the obtained values of general tolerance, and then finally add or correct dimensions on the actual manufacture drawings. It is highly possible that workers read wrong values of general tolerance by mistake when they go through the list. The standards lists are often kept at offices apart from worksites, or in reality they cannot easily be carried, in other words, they are not easy to use for the workers.

[0006] Therefore, in the conventional manner, accurate dimensional information necessary for producing high quality products, in other words, limits of size are not easily available to the workers.

[0007] It is therefore a main object of the present invention to provide a tolerance display system that allows accurate dimensional information to be easily available to workers in actual worksites.

DISCLOSURE OF THE INVENTION

[0008] A tolerance display system according to the invention includes storage means storing standards data/files related to a general tolerance, information input means for inputting prescribed information, operation means for reading out standards data related to the general tolerance from the storage means based on data input by the information input means, and calculating limits of size, output means for displaying the input data, the standards data, and the limits of size, and control means for managing/controlling the storage means, the input means, the operation means and the output means. The information input means includes an industry kind menu input portion for selecting and inputting an industry kind represented by the kind of a desired product, a specified condition input portion for inputting a specified condition such as a special item, a tolerance class, and a basic dimension, and a numerical value/arithmetic operator input portion for inputting a numerical value/an arithmetic operator.

[0009] In the above tolerance display system, the industry kind menu input portion may include an industry kind menu input keyboard for selecting an industry kind, for example, represented by the name of a desired product., the numerical value/arithmetic operator input portion may include a numerical value/arithmetic operator input keyboard for inputting a numerical value/an arithmetic operator, and the specified condition input portion may include a special item input keyboard for inputting a special item such as the kind of a shape, the kind of a product, the kind of a working method, the kind of a material, the kind of a size, and the kind of a geometrical characteristic, a basic dimension division input keyboard for selecting the division of a basic dimension, a tolerance class input keyboard for selecting a tolerance class and a general tolerance input keyboard for inputting a calculated general dimensional tolerance.

[0010] In the above tolerance display system, the standards data may automatically be retrieved based on each input data, and a calculation processing for limits of size related to the special item of the input industry kind menu may be carried out.

[0011] In the above tolerance display system, it is more effective that the input data, the retrieved standards data, the limits of size obtained by the calculation processing and the unit thereof are displayed by the output means.

[0012] In the tolerance display system according to the invention, using the industry kind menu input portion, an industry kind for example represented by the kind of a desired product is selected, and any of standards data/files stored in the storage means in advance is accessed in order to specify the range of application for specifying general dimensional tolerance for the desired product. Then, using the information input means, prescribed specified conditions are input, and desired standards data related to the specified conditions are automatically retrieved. Then, using the operation means, retrieval/calculation result information such as general tolerance and limits of size based on the general tolerance is obtained. The retrieval/calculation result information thus obtained is displayed by the output means.

[0013] The foregoing and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a diagram showing one embodiment of the invention;

[0015]FIG. 2 is a system flowchart for use in illustration of the embodiment shown in FIG. 1;

[0016]FIG. 3 is a system flowchart for use in illustration of the embodiment shown in FIG. 1, continued from FIG. 2;

[0017]FIG. 4 is a system flowchart for use in illustration of the embodiment shown in FIG. 1, continued from FIG. 3;

[0018]FIG. 5 is a system flowchart for use in illustration of the embodiment shown in FIG. 1, continued from FIG. 4;

[0019]FIG. 6 is a system flowchart for use in illustration of the embodiment shown in FIG. 1, continued from FIG. 5; and

[0020]FIG. 7 is a system flowchart for use in illustration of the embodiment shown in FIG. 1, continued from FIG. 6.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021]FIG. 1 is a diagram showing one embodiment of the present invention.

[0022] A tolerance display system according to the embodiment includes a tolerance display device 10. The tolerance display device 10 has a digital calculator function like a desktop calculator capable of carrying out the four arithmetic operations and is in an easy to carry, compact, twofold (double spread) form, for example. Therefore, the tolerance display device 10 can easily be carried by a worker in an actual worksite and provide high operability.

[0023] The tolerance display device 10 includes storage means storing standards data/files related to general tolerance according to national standards such as Japanese Industrial Standards (JIS). The storage means has a ROM file, for example. The ROM file pre-stores various standards data including special items in connection with the general tolerance. The data includes lists of divisions of basic dimensions, tolerance classes, general dimensional tolerance and the like specified by JIS, product names, working methods, the applicability of materials for each individual industry kind to which the standards data is applied, general items, terminology, instructions on drawings, notes, and the like.

[0024] Note that RAM files may be used instead of ROM files. The tolerance display device 10 according to the embodiment has a minimum calculation function to carry out four arithmetic operations for twelve digit numbers, for example. The device 10 includes storage means having a minimum storage capacity about in the range from 512 KB to 1024 KB, for example.

[0025] The tolerance display device 10 includes information input means for inputting various kinds of standards data related to the above general tolerance and prescribed specified information in association with the data, so that the data can be effectively utilized. For example, the information input means includes an industry kind menu input keyboard 12 as a first input portion (industry kind menu input portion) for selecting and inputting an industry kind menu represented by a product name for a desired industry kind. The industry kind menu input keyboard 12 is provided on the upper right side of the tolerance display device 10.

[0026] There is a specified condition input keyboard group 14 as a second input portion (specified condition input portion) provided near the industry kind menu input keyboard 12 for inputting specified conditions such as a product name, a special item, a basic dimension, and a tolerance class. The specified condition input keyboard group 14 includes a special item input keyboard 16 used to input a special item such as a working method and a material, a basic dimension input keyboard 18 used to input the division of a basic dimension, and a tolerance class input keyboard 20 used to input a tolerance class. There is a numerical value/arithmetic operator input keyboard 22 as a third input portion (numerical value/arithmetic operator input portion) used to input individual numerical values, or carry out an arithmetic operation on the left side of the tolerance display device 10.

[0027] Note that these various input keyboards are formed and arranged so that characters, symbols, drawings and the like are visually simple and calculation can be carried out by simple operation.

[0028] The tolerance display device 10 has operation means that reads out standards data related to a general tolerance from the storage means based on data input by the information input means, and calculates limits of size for a working method for a desired product using a stored limits of size calculation program/file or the like. An upper part of the numerical value/arithmetic operator input keyboard 22 is an input/output display screen 24. The screen serves as output means for displaying various kinds of input/output data such as input data, standards data related to general tolerance and limits of size. Note that the input/output display screen 24 according to the embodiment is a liquid crystal display screen having a display function for about 128×64 dots, for example.

[0029] The tolerance display device 10 has control means for managing/controlling so that the storage means, the information input means, the operation means and the output means operate in a regulated manner and appropriately in cooperation with each other. According to the embodiment, the operation means and the control means are implemented by a single central processing unit (CPU).

[0030] In the tolerance display device 10, an industry kind menu desired to be activated is selected using the industry kind menu input keyboard 12 and then standards data/files related to pre-stored general tolerance are accessed. Then, using the specified condition input keyboard group 14, prescribed specified conditions are input. Then, specified products, working methods, material names, divisions of basic dimensions, tolerance classes and the like are automatically retrieved on the database related to the input specified conditions and displayed on the input/output display screen 24 as retrieval result information. The retrieval result on the input/output display screen 24 is checked as required, and this operation is repeated a number of times, so that desired limits of size (allowable maximum size and allowable minimum size) are finally available to the user (worker).

[0031] With reference to the flowcharts in FIGS. 2, 3, 4, and 5, a system for calculating general dimensional tolerance, for example, for a parts formed by press working from sheet metal and limits of size based thereon will be described as an example of a tolerance display system using the tolerance display device 10 according to the embodiment.

[0032] The power supply key (AC) of the numerical value/arithmetic operator input keyboard 22 is turned on. Keys at the industry kind menu input keyboard 12 are pressed to command program activation and activates the limits of size calculation program/file. According to the procedure displayed on the input/output display screen 24, various kinds of data are input such as an industry kind (product name)=parts formed by press working from sheet metal, a special item (kind of press working)=punching, a basic dimension=50 mm, and tolerance class=A. Then, the worker is requested to check whether the content of the input condition specifications is correct on the input/output display screen 24.

[0033] When the content of the input condition specifications is confirmed to be correct, an input condition specification confirmation key 26 is pressed once to enter OK. In this case, the “OK” is indicated on the input/output display screen 24 in response to the single pressing of the input condition specification confirmation key 26. When the key is pressed twice, “NO” is indicated. In that case, the execution key 28 may be pressed after the displayed content is confirmed. Then, a corresponding general dimensional tolerance of ±0.15 (unit: mm) is retrieved from standards data/files related to the general dimensional tolerance, and displayed together with the basic dimension on the input/output display screen 24. According to the procedure displayed on the input/output display screen 24, the thus retrieved general dimensional tolerance, ±0.15 is input using the numerical value/arithmetic operator input keyboard 22 and the execution key 28 is pressed. Then, calculated data for the range of actual working sizes (allowable maximum and minimum size (unit: mm)) is displayed on the input/output display screen 24.

[0034] After acknowledging the desired limits of size, the worker selects whether or not to continue the operation. When the operation is to end, the operation end key 30 is pressed to end the operation. The operator then starts manufacturing the product based on the calculated actual working sizes (allowable maximum and minimum size (unit: mm)). If the operation is to be continued, the control returns to the initial operation and keys on the industry kind menu input keyboard 12 are once again pressed to activate the activation program, and the above flow may be repeated according to the procedure displayed on the input/output display screen 24.

[0035] The conventional systems depend on the worker's expertise or sense or the worker's efforts to find general dimensional tolerance by referring to JIS standards lists, and add or correct sizes displayed on actual manufacture drawings. In this way, necessary working sizes, in other words, limits of size are obtained. Meanwhile, by the tolerance display system according to the embodiment, the following effects are provided.

[0036] More specifically, the effects of the tolerance display system according to the embodiment are:

[0037] (1) Data such as product names, working methods, material kinds, tolerance classes, symbols, descriptions, divisions of basic dimensions, general dimensional tolerance, remarks, and notes is formed into databases, and therefore necessary working size information is available without much effort simply by operating the information input means. As a result, the time required for checking can significantly be shorter than the conventional methods.

[0038] (2) Since the JIS standards data related to general tolerance is provided in the form of databases, errors such as reading wrong values which are likely to happen in the course of manually checking the actual JIS standards lists can be prevented.

[0039] (3) Since the program used to calculate limits of size (allowable maximum and minimum size) based on general tolerance is stored, calculation can be carried out by inputting necessary information using the information input means. As a result, calculation mistakes can significantly be less than the case of calculating individual values.

[0040] Note that in the described embodiment, the tolerance display system using Japanese Industrial Standards (JIS) is used as an example of standards related to tolerance. Meanwhile, the invention is not limited to this, and standards data related to tolerance employed in a country of interest can be used among various other countries to which the tolerance display system is applied.

[0041] More specifically, in the tolerance display system according to the invention, standards data/files that can be stored in the storage means include those related to various tolerance, for example by American National Standards Institute (ANSI), Chinese Industrial Standards (CIS), Korean National Standards (KS), German Institute for Standardization (DIN), British Standards Institution (BSI), Italian National Agency of Unification (Unificazione Italiano, UNI), European Standards (EN), and International Organization for Standardization (ISO).

INDUSTRIAL APPLICABILITY

[0042] As in the foregoing, according to the invention, the tolerance display system that allows workers to easily obtain accurate size information in actual worksites is provided. Therefore, the tolerance display system according to the embodiment eliminates errors caused by careless mistakes by the workers, and therefore the workers can feel at ease during working. Therefore, losses by defects can significantly be reduced, and considerably high quality products can be manufactured. 

1. A tolerance display system, comprising: storage means storing standards data/files related to a general tolerance; information input means for inputting prescribed information; operation means for reading out standards data related to said general tolerance from said storage means based on data input by said information input means, and calculating limits of size; output means for displaying said input data, said standards data, and said limits of size; and control means for managing/controlling said storage means, said input means, said operation means and said output means, said information input means comprising: an industry kind menu input portion for selecting and inputting an industry kind represented by the kind of a desired product; a specified condition input portion for inputting a specified condition such as a special item, a tolerance class, and a basic dimension, and a numerical value/arithmetic operator input portion for inputting a numerical value/an arithmetic operator.
 2. The tolerance display system according to claim 1, wherein said industry kind menu input portion comprises an industry kind menu input keyboard for selecting an industry kind represented by a name of a desired product, said numerical value/arithmetic operator input portion comprises a numerical value/arithmetic operator input keyboard for inputting a numerical value/an arithmetic operator, and said specified condition input portion comprises a special item input keyboard for inputting said special item of interest such as the kind of a shape, the kind of a product, the kind of a working method, the kind of a material, the kind of a size, the kind of a geometrical characteristic, a basic dimension division input keyboard for selecting the division of said basic dimension, a tolerance class input keyboard for selecting said tolerance class and a general tolerance input keyboard for inputting a calculated general dimensional tolerance.
 3. The tolerance display system according to claim 1 or 2, wherein said standards data is automatically retrieved based on said input data, and a calculation processing for limits of size related to the special item of said input industry kind menu is carried out.
 4. The tolerance display system according to any one of claims 1 to 3, wherein said input data, said retrieved standards data, said limits of size obtained by the calculation processing and the unit thereof are displayed by said output means. 